There are several active threads right now on 650b Epics. Even though yours is an M4 generation, I believe the swingarm is the same as the newer ones. I have a 2005 S-Works Epic and my 650b wheelset should be here any day. I'll post pics of the fit with both the QuasiMoto and NeoMoto.

I wanted to give y'all an update on the conversion. I put in 50 miles over the last couple of days on it, even with the slight rubbing when the rear swing arm comes up. The bike rode awesome but fear I would wear out the new Qusimoto with the rubbing. Going to put the 26 back on the rear and hope it rides as well with just the 650B up front.

I have Vassago Bandersnatch on the way might try the 650B on the rear.

Bringing back an old thread. I have a 2003 Epic Comp and am wanting to convert the wheels to 650b. Anyone have anymore info they can share about their experience with up-sizing to 650b with a 2003-2006 Epic M4 aluminum frame?

I did a 650bEpic a few years ago with good results (search my user name for posts and pics of the build). I ended up really liking the 650B front tire all the time, but switched between 26 and B rear wheel depending on conditions. There isn't much room for mud or a big tread on the rear arch.

Hi Woodsskier, thank you for your reply. Yes, your 2010 is a much different frame design than my 2003. It may not work for you but I'm hoping that with the right tire I may be able to make a 650b fit with my frame and fork.

The original poster, C_CUB, asked about his 2003 Epic which should be the same as mine. So based on C_CUB's feedback he was close to getting this to work with only getting the tire to rub when the suspension is compressed.

I know there is a lot of variation in the tire side wall height which could make all the difference.

I've also contacted some tire vendors and am asking what the OD of their 650b tire is when inflated to 34 psi (or whatever psi they might have data for)

Just found this thread. I'm getting ready to convert my wife's 2004 Epic to 650b. The easy way to get rid of the rubbing on the seat post is to put some bottom out shims in the rear shock. You can use nylon washers from Lowe's for this. There are threads out there that can walk you through it. If you can't find it let me know - I did it on the rear shock on my Ibis Mojo and it would be the exact same. Really easy to do.

What I am wondering is what specific tires will clear the bridge connecting the seat stays. The schwalbe racing ralph's rub ever so slightly. I need a tire just a little bit smaller. Anybody had success with others or any input?

msbihli, I forgot to post here but I mounted a set of 650b wheels to my 2003 Epic and it did not go well. The wheels and tires were off a new bike at a bike shop so I didn't check which tires were mounted but the problem was not with the tires.

As soon as the suspension compressed with just my weight (sag) the link was really close to the tire and would rub the tire when riding over any small bumps. There was no issue with the tire on the seat post, it never got that close as it hit the link first.

As for adding spacers to limit shock travel, it would be too much of a comprimise since I feel there would not be enough suspension travel leftover to do the job. The newer Epics (2009 and higher) that have the shock mounted in the front triangle work fine as the suspension linkage is totally different.

I've since given up on 650b as I determined I like my 26" Epic the way it is and instead built a Carbon HT 29er.

Thanks for the reply Epic_Dude. I already put the 650b's on my wife's bike (taken off of my bike) and took it for a quick spin (without brakes - which made it "fun"). It ran well other than the tire slightly rubbing the bridge.

I also fully deflated the shock afterward and found that the only interference other than the bridge that I mentioned earlier is the welded aluminum lug on the seat post that supports the mounts for the link. I did not encounter any issue with hitting the link with the tire like you say in your post. There must be some difference between the two bikes that causes this. My wife's bike is a women's design and is a 2004 frame, so perhaps the link is slightly different than yours to gain a different leverage ratio for women riders.

The 650b's I put on are Stan's ZTR Crest with Schwalbe Rocket Ron's (2.25).